This invention relates to a combination shock absorber and air spring which is adapted for use in a vehicle suspension system and, particularly to a method of assembling the same.
A combination shock absorber and air spring usually comprises a tubular shock absorber having an outer tube and a piston rod reciprocably projecting from one end of the outer tube, and an air spring consisting of a resilient diaphragm member having an outer wall portion connected to a cylindrical housing which is secured to the projecting end of the piston rod, an inner concentric wall portion secured to the outer tube of the shock absorber, and a rolling wall portion formed between the inner and outer wall portions.
A typical prior art method of assembling the combination shock absorber and air spring comprises the steps of, as shown in U.S. Pat. Nos. 3,313,536 and 3,967,363, inserting the outer tube of the shock absorber into a tubular resilient diaphragm member, securing one end portion of the diaphragm member to the outer tube, clamping the other end portion of the resilient diaphragm member to radially outwardly expand and to pull backward, thereby forming the rolling wall portion and the outer wall portion, and, thereafter, securing the free end of the outer wall portion to the cylindrical housing. However, there are shortcomings such that the process clamping of the other end portion of the diaphragm member and radially outwardly expanding and pulling backward the same is relatively difficult, and that the clamped end portion of the diaphragm member will sometimes be damaged. Further, since the outer tube of the damper is substantially covered by the diaphragm member in fitting the diaphragm member on the outer tube of the shock absorber, it thus is difficult to employ the method on a shock absorber having a spring seat, a knuckle spindle or the like secured to the outer tube of the shock absorber. In the prior art method, such parts have been secured to the outer tube after assembling the shock absorber and the air spring, thereby complicating the assembling operation.